According to TCP and COF using a tape-shaped base member, a semiconductor package is fabricated, for example, using a polyimide tape having a width of about 35 mm. A copper foil or a copper plating layer is formed on the polyimide tame to form an electric circuit thereon. According to a TCP type of semiconductor package, a polyimide tape is removed at an area for a semiconductor chip, and copper leads connected to the semiconductor chip are exposed, which is called “flying lead structure”. On the other hand, according to a COF type of semiconductor package, a polyimide tape remains at an area for a semiconductor chip, which is not a “flying leads structure”.
FIGS. 1 and 2 show a conventional COF type of semiconductor package 10, hereinafter called “COF package”. FIG. 1 is a perspective view, while FIG. 3 shows a couple of COF package 10 connected to each other. In FIG. 1, a reference numeral 11 represents a semiconductor chip; and a reference numeral 12 represents bump electrodes formed on the semiconductor chip 11. A reference numeral 14 represents a flexible base film (base tape), which may be made of an insulating material such as a polyimide resin and a glass epoxy resin; a reference numeral 13 represents conductive leads formed on the base film 14; and a reference numeral 16 represents a solder resist for protecting the conductive leads. The solder resist 16 is formed, as shown in FIG. 1, to cover a surface of the package except an area on ends of the conductive leads 13 and surroundings.
Inner leads 17 are connected to the bump electrodes in a thermocompression bonding process. A sealing resin 15 is formed on upper and side surfaces of the semiconductor chip 11 to cover the semiconductor chip. A reference numeral 18 represents input terminals to be connected to an input circuit board; and a reference numeral 19 represents output terminals to be connected to an output circuit board. The tape (base film) is proved at its sides with perforations holes (sprocket holes) 20, which are used when conveying the base film. The perforation hoes 20 are arranged to have a pitch of 4.75 mm, in general.
An individual COF package 10 has a length of 17 mm. However, since COF packages are formed on a base tape, as shown in FIG. 2, each of divided COF packages has a length of 19 mm. That is because, the pitch of the perforation holes 20 is 4.75 mm and four perforation holes are arranged on each COF package. Practically, base film is shaped to have a length of 40 to 80 m with a number of COF packages each having a length of 19 mm.
As described above, according to the conventional COF package, even thought an effective package size (length) is 17 mm, the perforation holes 20 cause a worthless space corresponding to a multiple of 4.75 mm. In other words, each of the COF package is shaped to have a length of 19 mm including a worthless length of 2 mm.
For conveying a tape carrier, in addition to the above-describe type of structure using sprocket holes, a type of device which is carried using rollers has been proposed.
In patent applications, JPH06-310570A and JP2003-229441A, a tape carrier is conveyed by a roller mechanism.
[Patent Publication 1] JPH06-310570A
[Patent Publication 2] JP2003-229441A
According to a structure shown in Patent Publication 1, since sprocket holes are provided at a region where a roller is to be in contact with, there were the following problems.    (1) The strength of a tape is lowered by sprocket holes.    (2) Unevenness over the sprocket holes makes vibration in a conveying process, and therefore, a tape is hardly conveyed smoothly.
Further, according to a structure shown in Patent Publication 2, the same or similar problems as the Patent Publication 1 arise.